diff options
| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2023-03-22 22:45:45 +0100 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2023-03-23 14:44:43 +0100 |
| commit | 1271a7b98e7989ba6bb978e14403fc84efe16e13 (patch) | |
| tree | f5dddb574ebd830743af205b0ba19b913c742596 /drivers/pwm | |
| parent | 8caa81eb950cb2e9d2d6959b37d853162d197f57 (diff) | |
| download | lwn-1271a7b98e7989ba6bb978e14403fc84efe16e13.tar.gz lwn-1271a7b98e7989ba6bb978e14403fc84efe16e13.zip | |
pwm: Zero-initialize the pwm_state passed to driver's .get_state()
This is just to ensure that .usage_power is properly initialized and
doesn't contain random stack data. The other members of struct pwm_state
should get a value assigned in a successful call to .get_state(). So in
the absence of bugs in driver implementations, this is only a safe-guard
and no fix.
Reported-by: Munehisa Kamata <kamatam@amazon.com>
Link: https://lore.kernel.org/r/20230310214004.2619480-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/core.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index e01147f66e15..474725714a05 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -115,7 +115,14 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) } if (pwm->chip->ops->get_state) { - struct pwm_state state; + /* + * Zero-initialize state because most drivers are unaware of + * .usage_power. The other members of state are supposed to be + * set by lowlevel drivers. We still initialize the whole + * structure for simplicity even though this might paper over + * faulty implementations of .get_state(). + */ + struct pwm_state state = { 0, }; err = pwm->chip->ops->get_state(pwm->chip, pwm, &state); trace_pwm_get(pwm, &state, err); @@ -448,7 +455,7 @@ static void pwm_apply_state_debug(struct pwm_device *pwm, { struct pwm_state *last = &pwm->last; struct pwm_chip *chip = pwm->chip; - struct pwm_state s1, s2; + struct pwm_state s1 = { 0 }, s2 = { 0 }; int err; if (!IS_ENABLED(CONFIG_PWM_DEBUG)) @@ -530,6 +537,7 @@ static void pwm_apply_state_debug(struct pwm_device *pwm, return; } + *last = (struct pwm_state){ 0 }; err = chip->ops->get_state(chip, pwm, last); trace_pwm_get(pwm, last, err); if (err) |